Are these NEET questions free to attempt?

Yes. You can attempt every NEET question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.

Do I need an account to practise NEET MCQs?

No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.

Are these previous year NEET questions?

The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.

NEET NEET Questions — Free MCQ Practice

● ● ● ● ●

Two slits, 4 mm apart, are illuminated by light of wavelength 6000 Å. What will be the fringe width on a screen placed 2m from the slits

A.

0.12 mm

B.

0.3 mm

C.

3.0 mm

D.

4.0 mm

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$β = \frac{λ D}{d} = \frac{6000 \times 10^{- 10} \times 2}{4 \times 10^{- 3}} = 3 \times 10^{4} m = 0 .3 m m$

● ● ● ● ●

In the Young’s double slit experiment with sodium light. The slits are 0.589 m a part. The angular separation of the third maximum from the central maximum will be (given λ = 589 nm)

A.

$\sin^{- 1} (0 .33 \times 10^{8})$

B.

$\sin^{- 1} (0 .33 \times 10^{- 6})$

C.

$\sin^{- 1} (3 \times 10^{- 8})$

D.

$\sin^{- 1} (3 \times 10^{- 6})$

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

Using relation, $d \sin θ = n λ \Rightarrow \sin θ = \frac{n λ}{d}$

For n = 3, $\sin θ = \frac{3 λ}{d} = \frac{3 \times 589 \times 10^{- 9}}{0 .589}$

= 3 × 10^–6 or $θ = \sin^{- 1} (3 \times 10^{- 6})$

● ● ● ● ●

If the sodium light in Young’s double slit experiment is replaced by red light, the fringe width will

A.

Decrease

B.

Increase

C.

Remain unaffected

D.

First increase, then decrease

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$B \propto λ$

● ● ● ● ●

In Young’s double slit experiment the wavelength of light was changed from 7000 Å to 3500 Å. While doubling the separation between the slits which of the following is not true for this experiment

A.

The width of the fringes changes

B.

The colour of bright fringes changes

C.

The separation between successive bright fringes changes

D.

The separation between successive dark fringes remains unchanged

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$β \propto \frac{λ}{d}$

● ● ● ● ●

In Young’s double-slit experiment, an interference pattern is obtained on a screen by a light of wavelength 6000 Å, coming from the coherent sources S₁ and S₂. At certain point P on the screen third dark fringe is formed. Then the path difference S₁P – S₂P in microns is

A.

0.75

B.

1.5

C.

3.0

D.

4.5

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

For dark fringe at P

$S_{1} P - S_{2} P = Δ = (2 n - 1) λ / 2$

Here n =3 and λ = 6000

So, $Δ = \frac{5 λ}{2} = 5 \times \frac{6000}{2} = 15000 Å = 1 .5 m i c r o n$

● ● ● ● ●

In Young’s double-slit experiment the fringe width is β. If entire arrangement is placed in a liquid of refractive index n, the fringe width becomes

A.

$\frac{β}{n + 1}$

B.

nβ

C.

$\frac{β}{n}$

D.

$\frac{β}{n - 1}$

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$β = \frac{λ D}{d}$ and $λ \propto \frac{1}{μ}$

● ● ● ● ●

In Young’s double slit experiment, distance between two sources is 0.1 mm. The distance of screen from the sources is 20 cm. Wavelength of light used is 5460 Å. Then angular position of the first dark fringe is

A.

0.08°

B.

0.16°

C.

0.20°

D.

0.313°

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

Angular position of first dark fringe

$θ = \frac{λ}{d} = \frac{5460 \times 10^{- 10}}{0 .1 \times 10^{- 3}} \times \frac{180}{π}$ (in degree)

= 0.313°

● ● ● ● ●

In a Young’s double slit experiment, the slit separation is 0.2 cm, the distance between the screen and slit is 1m. Wavelength of the light used is 5000 Å. The distance between two consecutive dark fringes (in mm) is

A.

0.25

B.

0.26

C.

0.27

D.

0.28

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

Distance between two consecutive dark fringes $β = \frac{λ D}{d} = \frac{5000 \times 10^{- 10} \times 1}{0 .2 \times 10^{- 2}} = 0 .25$ mm.

● ● ● ● ●

A star emitting light of wavelength 5896 Å is moving away from the earth with a speed of 3600 km/sec. The wavelength of light observed on earth will

A.

Decrease by 5825.25 Å

B.

Increase by 5966.75 Å

C.

Decrease by 70.75 Å

D.

Increase by 70.75 Å

(c = 3 × 10⁸ m/sec is the speed of light)

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$ν' = ν \sqrt{(\frac{1 - \frac{v}{c}}{1 + \frac{v}{c}})} λ = λ \sqrt{(\frac{1 + \frac{v}{c}}{1 - \frac{v}{c}})} = λ \sqrt{(\frac{1 + \frac{3600}{c}}{1 - \frac{3600}{c}})} = λ \sqrt{\frac{1.012}{0.988}} = 1.012 λ = 70.75 \overset{o}{A}$

● ● ● ● ●

A heavenly body is receding away from the earth such that the fractional change in λ is 1, then its velocity is :

A.

C

B.

$\frac{3 C}{5}$

C.

$\frac{C}{5}$

D.

$\frac{2 C}{5}$

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$W h e n a p l a n e t r e c e d e s a w a y f r o m t h e e a r t h a n d f i s t h e f r e q u e n c y o f v i b r a t i o n : f = \frac{c}{λ} I f v = v e l o c i t y o f m o v i n g a w a y f r o m t h e e a r t h a n d λ' = a p p a r e n t w a v e l e n g t h t o a n o b e s e r v e r o n t h e e a r t h; λ' = \frac{c + v}{f} \Rightarrow λ' = (\frac{c + v}{c}) λ F r a c t i o n a l c h a n g e i n w a v e l e n t h = \frac{λ' - λ}{λ} = \frac{(\frac{c + v}{c}) λ - λ}{λ} = \frac{v}{c} = 1 \Rightarrow v = c$

NEET Practice Questions (MCQs) with Answers & Solutions

Frequently Asked Questions